Room Temperature Quantum Spin Hall Insulator in Ethynyl-Derivative Functionalized Stanene Films.
Room Temperature Quantum Spin Hall Insulator in Ethynyl-Derivative Functionalized Stanene Films.
复制标题
乙炔基衍生物功能化锡薄膜中的室温量子自旋霍尔绝缘体
DOI：
10.1038/srep18879
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发表时间：
2016-01-05
影响因子：
4.6
通讯作者：
Li F
中科院分区：
文献类型：
--
作者：
Zhang RW;Zhang CW;Ji WX;Li SS;Yan SS;Hu SJ;Li P;Wang PJ;Li F
量子自旋霍尔 (QSH) 绝缘体具有边缘态，可在拓扑上防止反向散射。然而，QSH效应应用的主要障碍是缺乏合适的大间隙QSH绝缘体。基于第一性原理计算，我们预测了乙炔基衍生物功能化锡烯（SnC2X；X = H、F、Cl、Br、I）中的一类大间隙 QSH 绝缘体，允许在室温下可行的应用。值得注意的是，SnC2Cl、SnC2Br和SnC2I是QSH绝缘体，其体能隙约为0.2eV，而SnC2H和SnC2F在拉伸应变下可以转变为QSH绝缘体。为这些系统的边缘建立了一对受拓扑保护的螺旋边缘态，狄拉克点位于体带隙处，其 QSH 态由拓扑不变量 Z2= 1 证实。BN 衬底上的薄膜还保持了非平凡的大间隙 QSH 效应，其中包含位于带隙内的狄拉克锥。这些发现可能为未来基于自旋电子学中二维蜂窝晶格的大间隙 QSH 绝缘体的设计和制造提供新的思路。
Quantum spin Hall (QSH) insulators feature edge states that topologically protected from backscattering. However, the major obstacles to application for QSH effect are the lack of suitable QSH insulators with a large bulk gap. Based on first-principles calculations, we predict a class of large-gap QSH insulators in ethynyl-derivative functionalized stanene (SnC2X; X = H, F, Cl, Br, I), allowing for viable applications at room temperature. Noticeably, the SnC2Cl, SnC2Br and SnC2I are QSH insulators with a bulk gap of ~0.2 eV, while the SnC2H and SnC2F can be transformed into QSH insulator under the tensile strains. A single pair of topologically protected helical edge states is established for the edge of these systems with the Dirac point locating at the bulk gap and their QSH states are confirmed with topological invariant Z2= 1. The films on BN substrate also maintain a nontrivial large-gap QSH effect, which harbors a Dirac cone lying within the band gap. These findings may shed new light in future design and fabrication of large-gap QSH insulators based on two-dimensional honeycomb lattices in spintronics.